WO2005/102605 discloses a power tool which drives a tool accessory held by a work spindle and a fastening element. In this power tool, the fastening element can slide with respect to the work spindle between a clamped position in which the tool accessory is held and an open position in which the tool accessory is removed from the work spindle. In the clamped position, a retaining assembly provided inside the work spindle clamps a clamp shaft of the fastening element. Specifically, the retaining assembly provided inside the work spindle holds the fastening element using a clamping force which is applied by a spring element provided inside the work spindle. The tool accessory is held in this manner between the work spindle and the clamping element. When a cock lever is operated, this retaining assembly unclamps the clamping element through axial displacement of a thrust member.